1. Field of the Invention
[0001] The present invention is directed to a rod glow plug with a glow tube.
2. Description of the Prior Art
[0002] Rod glow plugs are generally known and have a glow tube in which there are heating coil(s) and optionally control coil(s) series connected to one another, the coils in the terminal-side area being connected to one terminal pole and in the glow tube tip being connected to the glow tube. Conventionally, the coils are embedded within the glow tube in an electrically insulating conductive material. In the area of the glow tube tip it first of all has an opening in which the coil end on the side of the combustion space is welded to the glow tube with the formation of a welding spot. This welding spot causes a heavy accumulation of material which adversely affects the preheating time of the plug. The high welding energy which must be applied for welding of the glow tube and the heating coil is likewise disadvantageous. Especially for long rod glow plugs and/or for heating coils with thin wires, centering of the heating coil in the area of the welding spot represents a major problem, the rod glow plugs often being faulty when the heating coil is not exactly centered.